Hispanics are the second largest and fastest-growing minority group in the U.S. However, until recently little information on their health status or use of health care services has been available for policy makers and administrators concerned with Hispanic health care. Beginning in 1976, the H.I.S. included an Hispanic ethnic identifier on the survey questionnaire, and now valuable national data are being routinely and systematically collected. This investigation will use this newly available data to examine differences in the utilization of ambulatory health care services between the Hispanic and non-Hispanic population groups. This investigation will be conducted as a descriptive analytic study. The primary data source is the National Health Interview. The study sample will consist of the Hispanic respondents to the H.I.S. aggregated over a three-year period to ensure an adquate sample size (yrs. 1978, 1979, 1980). The comparison group will consist of the non-Hispanic H.I.S. respondents to the 1979 survey. The specific aims include: 1) to assess whether Hispanics have equal access levels to ambulatory medical care services relative to their need for care, compared with the black and white non-Hispanic H.I.S. respondents to the 1979 survey. The specific aims include: 1) to assess whether Hispanics have equal access levels to ambulatory medical care services relative to their need for care, compared with the black and white non-Hispanics; 2) to identify differences in use among the Hispanic subgroups; and 3) to identify the factors that influence Hispanics' use of services including demographic, socioeconomic, residential and health status facros. Illness care and preventive care will be examined separately. Six indicators of use relative to need will be used in making comparisons in access levels among the groups. By identifying Hispanics' access to care relative to other U.S. population groups, and the factors associated with differential use, implications may emerge for targeting programs and policies toward specific Hispanic subgroups for whom barriers to care seem to exist.